GM Part Warranty
The standard warranty for most OEM replacement parts (be they GM brand or AC Delco brand) is at least 12 months with unlimited mileage, but there are parts with more coverage. GM replacement engines and transmissions, for example, can have 18 or 36 months of coverage with 100,000 miles. GM Performance Engines can be covered for 24 months or 50,000 miles.
Standard GM and AC Delco Part Warranty Coverage Info